certainty vs reality

certainty

noun
  • A fact or truth unquestionably established. 

  • The state of being certain. 

  • An instance of being certain. 

reality

noun
  • A real entity, event, or other fact. 

  • The entirety of all that is real. 

  • The real world. 

  • The state of being actual or real; realness. 

  • An individual observer's own subjective perception of that which is real. 

How often have the words certainty and reality occurred in a corpus of books? (source: Google Ngram Viewer )